Codecs process audio signals in a computer such as PCs and handheld devices. One of the primary functions of an audio codec is to convert both input and output audio signals to and from the internal digital signal format of the computer and the typically analog signal format of external devices plugged into the computer. The codec is typically embodied in a chip on the motherboard add-in/riser card along with one or more application circuits for the various jacks. The CPU, the processor, the memory, and the core logic are also typically motherboard level devices.
One method of connecting external audio devices to the computer is to use a 3.5 mm or similar stereo audio jack. Each computer contains several jacks, which have typically been dedicated to a single function each, such as a stereo line out for speakers, a microphone input, and a line input. With the increase in multimedia formats available today, there is a need for increasing the number of input and output audio devices that the computer can support without increasing the current number of jacks on the computer which would increase the cost of the system. Even with just a few jacks, computer users incorrectly connect external devices to the wrong jack which leads to costly support calls. Increasing the number of jacks on the computer would only increase the likelihood that a user would incorrectly connect an external device to the wrong jack further increasing the number of costly support calls.
In the patent application filed Jun. 19, 2003 referenced above and hereby incorporated herein by this reference, the applicant hereof discloses codec circuitry which uniquely measures the electrical characteristics of a device plugged into a jack as a way to identify the device. Then, a reconfigurable circuit is activated to make sure the identified device is correctly supported. The Intel Corporation, in the specification entitled “Audio Codec '97” (Rev 2.3, April 2002), also incorporated herein by this reference, calls the device identification data the “sensed bits.” Another Intel specification incorporated herein by this reference is entitled “First Generation Intel® Audio PnP User Model and Methodologies” (Rev 1.1, Aug. 12, 2002). That specification discloses, inter alia, the idea of prompting the user to verify that the identification of the device output by the codec is correct.
It would be possible to provide logic in the codec which compensates for the electrical characteristics of the application circuit when the electrical characteristics of a device plugged into the jack are measured by the codec to identify the device. But, as between different manufacturers and as between different production runs, the specific components of an application circuit can change and/or change in value. Accordingly programming the codec to compensate for a set of electrical characteristics subject to change is not a reliable solution. And, the Intel specification fails to teach or suggest an alternative solution: in fact it does not even identify the problem posed by the application circuit in making a device identification.
Finally, although the Intel specification discusses the idea of querying the user to verify the correctness of the identification made by the codec, it would be extremely awkward and annoying if the user had to make the same correction every time the user plugged in the same device. That is, if each time the codec incorrectly identified headphones as a speaker the user had to make the same correction each time the user plugged the headphones into the personal computer, the user would quickly become frustrated. The Intel specification also fails to identify this problem or a solution.
The subject invention solves both problems via a unique middleware application responsive to the codec driver and the user interface as an alternative to attempting to solve these problems at the codec/motherboard level.